Timer circuit that displays time using light dots

Circuit working principle: When S2 is closed, the timer is reset (C, discharge). The resistor is used to limit the peak discharge current
through the switch . Rs is used to compensate the leakage of electrolytic capacitor C to prevent VD. . not bright. If pin 9 is left empty, the time will be displayed in a "bright spot" mode, that is, as time passes, only one LED will always light up. After reset, VD lights up first, and then the other LEDs light up in sequence. At this time, the total current consumption of the timer is only 20 mA, and it can be powered by a battery. If pin 9 is connected to pin 3 (positive power terminal), the time will be displayed in the form of a "bright bar". After reset, all LEDs will light up, and then from VD, Start extinguishing one by one.